The present invention relates to apparatus for feeding signatures to the hopper of a large gathering machine of the type which is used in binderies, for example, gather folded signatures in the assembly of a magazine.
Gathering machines for use in binderies are well known, and they are arranged to have a number of stations, each provided with a hopper holding a number of signatures. The gathering machine takes one signature off the bottom of each hopper in sequence and assembles them into a magazine, book or catalog. It is desirable to maintain the height of signatures in each hopper within predetermined limits so that the weight of the signatures in a stack is generally fixed, and the amount of force necessary to remove a signature from the bottom of a stack is substantially constant. There is thus a reduced likelihood of jamming in the gather machine during the removal of signatures from a hopper.
Machines are known for supplying signatures to a hopper while maintaining the height of signatures in the hopper within predetermined limits. Normally, such machines provide a first or source stack at a location removed from the hopper of the gathering machine and some conveyor mechanism for feeding signatures from the source stack to the hopper of the gathering machine. The advantage of these machines is that a worker can load large quantities of signature into the source stack. Even though the total weight of the source stack may vary substantially, nevertheless, the height and weight of the hopper stack is controlled. This enables a single worker to tend a number of machines.
Such machines have been found advantageous for use in feeding signatures of heavy stock, but there usefulness does not extend to feeding signatures of lightweight stock such as are used in catalogs, for example. In feeding lightweight signatures of this type there is a tendency to buckle the signature, thereby complicating the problem of feeding from the bottom of the source stack, which, it will be recalled, may vary widely in height and weight. The present invention overcomes this problem and is capable of reliably feeding lightweight signatures from a source stack to the hopper of a gathering machine. This is accomplished mainly by feeding the signatures from the bottom of the source stack in a direction which is parallel to the backbone of the signature onto a main conveyor which feeds the signatures in shingled relation to the gathering machine hopper. By feeding the signatures from the source stack in the direction parallel to the backbone of the signatures, the signature backbone is used as a stiffener rib to prevent buckling. Because the main conveyor is operated continuously, and the signatures are fed onto the main conveyor in a direction transverse to the movement of the top flight of the conveyor, the signatures are automatically deposited in desired shingled relation on the conveyor.
A light source and photo cell combination is used to control the feeding of signatures from the source stack onto the main conveyor, and a second conveyor is used to feed the signatures from beneath the source stack. An inclined guide plate is used to direct the signatures from the source stack onto the main conveyor, and other features are incorporated to overcome the problems encountered in feeding lightweight signatures.
The present invention has, moreover, still another advantage. Due to the fact that the signatures are fed from the source stack in a transverse direction relative to the movement of the main conveyor, the hopper for the source stack is located to the side of the main conveyor--rather than in line of the main conveyor. According to the present invention, the source stack is arranged at a location elevated above the main conveyor, and the source stack conveyor is inclined upwardly and outwardly from the main conveyor. This not only facilitates feeding of signatures from the source stack onto the main conveyor, but it also permits the source stack to be located above the main conveyor of an adjacent hopper loader. Thus, the hopper loaders nest to reduce space requirements. It will be appreciated that the stations of the gathering machine are located as closely together as possible, so that hopper loaders must be correspondingly close together. In prior art machines which aligned the source stack to feed parallel to the feed direction of the main conveyor, the overall loader extended outwardly a considerable distance from the hopper of the gathering machine, thereby reducing space available for storing large quantities of signatures. Typically, large quantities of signatures are held on wooden pallets in the area immediately adjacent the hopper loader so as to minimize the distance over which a worker must travel to keep a hopper loader filled with signatures. The more space that is available for storing large quantities of signature, the more convenient it is not only to the worker but to the operators of the pallet trucks who must bring the signatures to each individual hopper loader.
Other features and advantages of the present invention will be apparent to persons skilled in the art from the following detailed description of a preferred embodiment accompanied by the attached drawing wherein identical reference numerals will refer to like parts in the various views.